Recently, the general trends in designing electronic devices are toward small size, light weightiness and easy portability. Moreover, with the increasing development of electronic industries, the internal circuitries of the electronic devices are gradually modularized. In other words, plural electronic components are integrated into a single electronic module. For example, a power module is one of the widely-used electronic modules. An example of the power module includes but is not limited to a DC-to-DC converter, a DC-to-AC converter or an AC-to-DC converter. After the electronic components (e.g. capacitors, resistors, inductors, transformers, diodes and transistors) are integrated as a power module, the power module may be installed on a motherboard or a system circuit board.
Conventionally the electrical connection inside an electronic module is made by wire bonding. Recently an embedded approach, which is without any bonding wire, is being employed in packaging to further reduce the package foot-print and enhance the performance at the same time.
An embedded package structure of the power module will be illustrated as follows. In the package structure, an electronic component with at least one conducting terminal is disposed on a first surface of a substrate, and a first insulation layer is disposed on the first surface of the substrate. If necessary, a second insulation layer is disposed on a second surface of the substrate. The electronic component is covered by the first insulation layer. For allowing the conducting terminal to be connected with an external circuit, at least one conductive via is formed in the first insulation layer by a laser drilling process. Moreover, after the at least one conductive via is cleaned by a desmearing process with a chemical agent, a conductive material is formed in the conductive via by a filling process or an electroplating process. Consequently, the conducting terminal of the electronic component may be connected with the external circuit through the conductive via.
As mentioned above, for allowing the conducting terminal of the embedded electronic component to be connected with the external circuit, the conductive via is formed in the first insulation layer by the laser drilling process, and the conductive via is cleaned by the desmearing process with the chemical agent. Since copper has excellent resistance to the laser drilling process, the conducting terminal of the electronic component of the embedded package structure is usually made of copper. In other words, the possibility of causing damage of the conducting terminal of the electronic component during the laser drilling process will be minimized. Moreover, since copper has excellent resistance to the chemical agent during the desmearing process, the possibility of causing corrosion by the chemical agent will be minimized. Moreover, the native oxide layer on the copper surface is easily removable by etching process.
However, since the conducting terminal of the embedded electronic component of the package structure is made of copper, the type of the electronic component is restricted. If the conducting terminal is made of a non-copper metallic material, the electronic component cannot be directly embedded within the package structure. In particular, if the conducting terminal of the electronic component is made of the non-copper metallic material and the electronic component needs to be embedded in the package structure, the conducting terminal of the electronic component should be firstly treated and then replaced by copper. Under this circumstance, the fabricating process of the package structure is complicated.
Therefore, there is a need of providing an improved package structure in order to eliminate the above drawbacks.